Field of the Invention
The present invention relates to an electric rotating machine that can function while performing, as occasion demands, switching between a motor mode where a vehicle power source or the like supplies electric power to the electric rotating machine so that the electric rotating machine functions as a motor and an electric power generator mode where an engine or the like mounted in the vehicle supplies motive power to the electric rotating machine so that the electric rotating machine functions as an electric power generator, and relates to a control method for the electric rotating machine.
Description of the Related Art
An electric rotating machine, which can function while performing switching between the motor mode and the electric power generator mode and is referred to as a so-called motor generator, is well known. Such an electric rotating machine is mounted in a vehicle such as an automobile and is supplied with electric power from a vehicle power source apparatus such as a vehicle battery so as to function in the motor mode and to perform engine starting and a torque assist for the engine; on the other hand, its rotor is rotation-driven so that it functions in the electric power generator mode so as to charge the vehicle power source and to supply electric power to vehicle electric loads.
In recent years, in order to raise the gasoline mileage of a vehicle and to make a vehicle conform to the environmental standard, there has been developed a vehicle that performs a so-called idling stop in which the engine thereof is stopped when the vehicle is stopped and the engine thereof is restarted when the vehicle is started again. In a vehicle that performs an idling stop, instead of a vehicle electric power generator having only the function of an electric power generator, an electric rotating machine as the foregoing motor generator is mounted; the electric rotating machine is made to function in the electric power generator mode so as to supply electric power to vehicle electric loads and a vehicle power source apparatus such as a battery; when the vehicle is restarted, the electric rotating machine is made to function in the motor mode so as to restart the engine.
It is required that such a vehicle electric rotating machine is small-size and inexpensive. Accordingly, as disclosed, for example, in Patent Document 1, as the control method for an electric rotating machine, a method of energizing the electric rotating machine with a rectangular wave current is adopted instead of a method of applying pulse width modulation to a sinusoidal wave, so that the configuration of an electric-power conversion unit that functions as an inverter or a converter and the control therefor are simplified and hence downsizing and cost saving of the electric rotating machine is achieved.
In order to raise the gasoline mileage, it is required to increase the output of an electric rotating machine; thus, the voltage of a vehicle power source apparatus such as a battery is raised so that the output of an electric rotating machine is increased. Furthermore, as disclosed in Patent Document 1, in the case where an electric rotating machine is made to function as an electric power generator, the magnetization direction of the magnetic-field current is reversed and the energization phase of a rectangular wave current to the armature winding is delayed so that the power-generation output of the electric rotating machine is raised.